Permission to reprint the abstract has not been received from the publisher.

The effect of income, education, employment, marital status, age, race, birth order, and national economic conditions on the sex ratio at birth were analyzed for the N = 21,597 children of the National Longitudinal Survey of Youth 1979 participants. These data were analyzed for individual births using a logistic regression model, treating the sex of each child as the outcome variable, and were analyzed for families using a linear regression model, treating the proportion of male children in each family as the outcome variable. No variable was statistically significantly related to the sex ratio. These findings suggest that the sex ratio at birth may not be affected by the individual- and population-level factors commonly examined in past research.

Permission to reprint the abstract has not been received from the publisher.

Increasingly, psychologists encounter data in which several individuals have been measured on multiple variables over numerous occasions. Many of the current methods for this situation combine the data, assuming everyone is a randomly equivalent to everyone else. The extreme alternative on the other side is to separately analyze each person's data, assuming no one is similar to anyone else. This dissertation proposes a method as a compromise between these two extremes. The goal of the method is to find people in the data that are undergoing similar change processes over time. Data were simulated under various conditions to explore what factors influenced the ability of the method to correctly estimate the change process and accurately find people with the same process. It was found that sample size had the greatest positive influence on parameter estimation and the dimension of the change process had the greatest positive impact on correctly grouping people together, likely due to the distinctiveness of their patterns of change. With some success in simulation, the method was applied to an archival data source reflecting cognitive growth in the National Longitudinal Survey of Youth Children data. This analysis suggested that the genetic effects operating between people on their cognitive development may be quite different from their within-person effects, but also revealed a limitation for the method on large sample sizes. Once software improvements are made to the method, its applicability to large, real data should be reevaluated. State space mixture modeling, in its current form, offers one of the best-performing methods for simultaneously drawing conclusions about individual change processes while also analyzing multiple people.

Bibliography Citation

Hunter, Michael D. State Space Dynamic Mixture Modeling: Finding People with Similar Patterns of Change. Ph.D. Dissertation, Department of Psychology, University of Oklahoma, 2014.

Is AFI All in the Family? A Multi-Level Family Study of Age of First Intercourse
Ph.D. Dissertation, Department of Psychology, University of Oklahoma, 2013.
Also: https://shareok.org/handle/11244/7913
Cohort(s):
Children of the NLSY79, NLSY79, NLSY79 Young Adult
Publisher:
Department of Psychology, University of OklahomaKeyword(s):
Adolescent Sexual Activity; Age at First Intercourse; Family Influences; Home Environment; Intelligence; Intergenerational Patterns/Transmission; Modeling, Multilevel; Siblings

Permission to reprint the abstract has not been received from the publisher.

The importance of the timing of first intercourse in one's life history, and its significance in relation to a number of fertility and social outcomes, has been established in a number of studies. Studies have attempted to untangle the factors that contribute to its timing, and only some of these studies explore the possibility of selection influences on this outcome. This study uses National Longitudinal Survey of Youth (NLSY) samples and multilevel survival models to evaluate predictors of age at first intercourse (AFI) at both the family and individual level. The family structure among the NLSY samples enables the use of a children of siblings type design so that we may also investigate the possible influence of selection effects. Intelligence and educational goals are often implicated as factors motivating adolescents and young adults to delay AFI. Extended family, maternal, and child intelligence variables are the predictor variables of focus in this study. Other variables include maternal AFI, measures of the home environment, and family income, as these variables also relate to the evaluation of educational goals. Gender and race are also included as control variables. None of the intelligence variables were found to be significant predictors of AFI, though interesting trends emerged. Maternal AFI was consistently a significant predictor across models, but was later identified as non-significant relative to average AFI at the maternal family level. Possible explanations for these findings are offered.

Bibliography Citation

Meredith, Kelly M. Is AFI All in the Family? A Multi-Level Family Study of Age of First Intercourse. Ph.D. Dissertation, Department of Psychology, University of Oklahoma, 2013..

Identification of a Flynn Effect in the NLSY: Moving from the Center to the Boundaries
Working Paper, Department of Psychology, University of Oklahoma, 2005
Cohort(s):
Children of the NLSY79
Publisher:
Department of Psychology, University of OklahomaKeyword(s):
Armed Forces Qualifications Test (AFQT); Digit Span (also see Memory for Digit Span - WISC); Flynn Effect; I.Q.; Intelligence; Memory for Digit Span (WISC) - also see Digit Span; Peabody Individual Achievement Test (PIAT- Math); Peabody Individual Achievement Test (PIAT- Reading); Tests and Testing

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The Flynn Effect (Flynn, 1984) is an annual increase in IQ of around .33 points per year observed in developed countries during the past century. It emerges from problem solving and non-verbal components of IQ. The cause has been argued, and a number of theories proposed. Rodgers (1998) noted that the search for causes has preceded specification of the nature of the effect. We use a large national sample of U.S. children to test for the Flynn Effect in PIAT Math, PIAT Reading Recognition, PIAT Reading Comprehension, Digit Span, and PPVT. An effect of the predicted magnitude was observed for nationally normed scores on each outcome, and on PIAT Math when maternal IQ was controlled. This finding in a large representative sample with thousands of variables opens the door to test a number of different hypotheses about the nature of and the causes of the Flynn Effect in both environmental and biological domains.

Bibliography Citation

Rodgers, Joseph Lee and Linda Gissberg. "Identification of a Flynn Effect in the NLSY: Moving from the Center to the Boundaries." Working Paper, Department of Psychology, University of Oklahoma, 2005.

Permission to reprint the abstract has not been received from the publisher.

DeFries and Fulker (1985) proposed DF Analysis to measure genetic and shared environmental variance in kinship data. We use an adaptation of DF Analysis that can simultaneously account for genetic, shared environmental, and nonshared environmental influences within the same model. We fit this model to achievement measures from 5 to 12-year-old children from the National Longitudinal Survey of Youth (NLSY). The NLSY is a large national sample containing information to link kinship pairs at multiple levels, including cousins, half-siblings, full-siblings, and twins. 1044 pairs were identified by a kinship linking algorithm. The modeling approach measures heritability (h2) and shared environmental variance (c2), and tests for nonshared environmental influences. Potential nonshared influences that are tested include amount a mother reads to a child, books the child has, visits to the museum, visits to the theater, maternal spanking, and a general measure of the quality of the home
environment. Several theoretical predictions are tested and supported. In particular, museum visits accounted for variance in a math test, books owned accounted for variance in reading recognition scores, and a general measure of the home environment accounted for variance in general cognitive ability.